Four-piece hot top with foldable subassemblies

ABSTRACT

This invention relates to a hot top of the type used to insulate the reservoir of an ingot mold into which molten steel is poured that consists of a pair of foldable wall section and corner post subassemblies which cooperate with one another and with two corner posts defining keys for the latter to produce a hollow truncated generally pyramidal enclosure. Each of the foldable subassemblies includes a single large fabric panel to one face of which is fastened in edge-to-edge relation a series of three wall sections while to the other face is attached a corner block opposite the middle of the three wall sections. The three sections are all generally trapezoidal with their adjacent edges oppositely inclined so as to mate in folded relation using the fabric panel as a hinge and define two 45* corners. The free edges of the outboard sections cooperate in a similar way with the adjacent edges of the corner posts. A novel hanger subassembly is provided on each of the two wall section and corner post subassemblies which includes a pair of apertures strap hangers molded in place between the fabric panel and each of the two end wall sections. The lower projecting ends of the hangers lock beneath their respective wall sections while the upper projecting apertured ends thereof receive rods that extend diagonally in supporting relation across the inner of the rim of the ingot mold reservoir. The invention also contemplates the method of making the hot top foldable subassemblies which includes the steps of impregnating the fabric panel with a heatresistant slurry, placing the wetted panel in the bottom of a pan, laying the hanger straps atop the panel, forming the three individual wall sections along with the joints therebetween atop the fabric panel and straps, curing the fabric panel and wall sections, fastening a corner block to the outside of the fabric panel in position to cooperate therewith and with the middle wall section on the inside thereof to form an integral corner post, and bending the projecting lower end of the hanger strap to form a hook supporting the wall section on its face.

United States Patent Mueller FOUR-PIECE HOT TOP WITH FOLDABLE SUBASSEMBLIES [75] Inventor: Fred A. Mueller, Canon City, C010.

[73] Assignee: Colorado Refractories Corporation, Canon City, C010.

[22] Filed: Aug. 11, 1971 [21] Appl. No.: 170,699

Primary Examiner-Robert D. Baldwin Attorney, Agent, or Firm-Edwards, Spangler, Wymore & Klaas [57] ABSTRACT This invention relates to a hot top of the type used to insulate the reservoir of an ingot mold into which molten steel is poured that consists of a pair of foldable wall section and corner post subassernblies which cooperate with one another and with two corner posts defining keys for the latter to produce a hollow truncated generally pyramidal enclosure. Each of the fold- 1 Bfli 5 Mar. 19, 1974 able subassemblies includes a single large fabric panel to one face of which is fastened in edge-to-edge relation a series of three wall sections while to the other face is attached a corner block opposite the middle of the three wall sections. The three sections are all generally trapezoidal with their adjacent edges oppositely inclined so as to mate in folded relation using the fabric panel as a hinge and define two 45 corners. The free edges of the outboard sections cooperate in a similar way with the adjacent edges of the corner posts. A novel hanger subassembly is provided on each of the two wall section and corner post subassemblies which includes a pair of apertures strap hangers molded in place between the fabric pane-1 and each of the two end wall sections. The lower projecting ends of-the hangers lock beneath their respective wall sections while the upper projecting apertured ends thereof receive rods that extend diagonally in supporting relation across the inner of the rim of the ingot mold reservoir. The invention also contemplates the method of making the hot top foldable subassemblies which includes the steps of impregnating the fabric panel with a heat-resistant slurry, placing the wetted panel in the bottom of a pan, laying the hanger straps atop the panel, forming the three individual wall sections along with the joints therebetween atop the fabric panel and straps, curing the fabric panel and wall sections, fastening a corner block to the outside of the fabric panel in position to cooperate therewith and with the middle wall section on the inside thereof to form an integral corner post, and bending the projecting lower end of the hanger strap to form a hook supporting the wall section on its face.

2 Claims, 9 Drawing Figures FOUR PIECE I-IOT TOP WITH FOLDABL SUBASSEMBLIES In my copending application Ser. No. 106,448 filed Jan. 14, 1971, now abandoned, I disclose a fabricreinforced eight-piece hot top to be used as an insulated lining for the interior surface of an ingot mold reservoir. This hot top has proven eminently satisfactory as far as the insulating qualities are concerned as well as its ability to hold together under normal use. It is, however, rather slow to install and requires a jig to hold the several parts in place while the posts are driven into the corners to complete the assembly.

On occasion, hot tops of the aforementioned type along with most others fit imperfectly inside the mold reservoir thus leaving gaps in the insulation through which heat can escape causing the pipe in the ingot to deepen. Of course, the sole function of the hot top is to keep the steel within the ingot mold reservoir in a molten state as long as possible so that it will continue to feed the ingot and reduce the depth of the pipe in the ingot. According'ly,'a poorly-fitted hot top is most undesirable and may even jiggle loose as the mold progresses from the set-up tables to the pouring tables.

Since some ingot molds look to be almost square in horizontal cross section but are not, occasionally the crew installing a multi-piece hot top will assemble it incorrectly because of the difficulty in distinguishing between the wall panels of different lengths. When this occurs, gaps are left at the joints between the wall panels and corner posts thus destroying the integrity of the insulation barrier. The various parts may even be stressed unequally to a degree where fractures occur in the panels or else the corner posts are broken in an attempt to drive them into the gap between two improperly matched panels.

It is not uncommon to find a residue of steel along the inside of the ingot mold reservoir rim that prevents the hot top from fitting snugly againstthe walls thereof unless some provision is made for lowering it to miss this mold imperfection. Few of the prior art hot tops including my own make any provision for vertical adjustment thereof relative to the reservoir rim.

Finally, the cost of manufacturing an eight-piece hot top as compared with, say, a four-piece one, is considerably greater. This fact coupled with the increased installation time for the one with the greater number of pieces mitigates heavily against the latter.

It has now been found in accordance with the teaching of the instant invention that these and other shortcomings of the prior art hot tops can, in large measure, be eliminated by using the fabric reinforcing panel as a hinge by means of which two wall sections and a corner post can be joined together in edge-to-edge foldable relation. Two such panel and corner post subassemblies along with a single pair of independent corner posts constitute the entire hot top except for the hanger unit thus reducing the number of comparable parts from eight to four. The integrity of the insulation barrier is much improved over the prior art units and this, in turn, results in a more uniform ingot with less pipe. I

From a time standpoint, installation is much faster as no jig is needed to hold the several elements in position while two, rather than four, corner posts are driven into place. Also, the manufacture is, likewise, simpler and less expensive because very little more work is required to mold two wall sections and a corner section therebetween on a single fabric panel than to mold one of the wall panels separately. 7

The height of the hot top can be adjusted to allow ingots of varying heights to be poured and also to avoid encrustations and other obstructions along the rim at the mouth of the ingot mold reservoir. The same hanger assembly that is responsible for this adjustable feature results in the hot top being much more securely suspended inside the ingot mold reservoir so as to resist the jiggling and jostling occasioned by moving the molds from the set-up area to the pouring tables.

Accordingly, it is the principal object of the present invention to provide a novel and improved four-piece hot top.

A second objective of the invention forming the subject matter hereof is to provide a unique method of fabricating a foldable wall section and corner post subasserribly that uses the fabric reinforcing panel as the hinge member therebetween.

Another object of the within-described invention is to provide a hot top that is simpler, easier and faster to make as well as to install.

An additional objective of the invention disclosed and claimed herein is the provision of an ingot mold hot top that provides a much improved insulation barrier around the inside of the reservoir than other multipiece hot tops.

Further objects are to provide a hot top that is rugged, efficient, relatively inexpensive and one that is readily adapted for use in various types, shapes and styles of ingot mold reservoirs.

Other objects will be in part apparent and in part pointed out specifically hereinafter in connection with the description of the drawings that follows, and in which:

FIG. 1 is a perspective view, portions of which have been broken away and shown in section to better reveal the interior construction, looking down and to the left upon the hot top of the present invention which has been illustrated in installed position inside the reservoir of an ingot mold;

FIG. 2 is a top plan view of the assembly shown in FIG. 1 that also reveals how the removable hanger bars across the opposite corners of the mold reservoir cooperate with their respective apertured hanger straps on each wall section and corner post subassembly to suspend the latter inside the mold while the independent corner posts are driven into place,

FIG. 3 is a front elevation showing the inside of one of the foldable wall section and corner post subassemblies in unfolded condition;

FIG. 4 is a top plan view of the subassembly of FIG.

FIG. 5 is a section to an enlarged scale taken along line 5'5 of FIG. 3;

FIG. 6 is an enlarged fragmentary section approximately the same scale as FIG. 3 showing the corner of the subassembly as it would appear looking down atop thereof;

FIG. 7 is a front elevation of one of the individual corner posts to the same scale as FIG. 6;

FIG. 8 is a side elevation of the corner post to the same scale; and,

FIG. 9 is a transverse section taken along line 99 of FIG. 7.

Referring next to the drawings for a detailed description of the present invention and, initially, to FIGS. 1 and 2 for this purpose, reference numeral has been chosen to represent broadly the hot top forming the subject matter hereof which has been illustrated in place within the reservoir 12 of an ingot mold. In the particular form shown, the mold has a reservoir of a truncated hollow pyramidal configuration that is slightly wider in one transverse dimension than the other. The comers 14 of the reservoir are rounded and are conical rather than spherical due to the taper of the mold upwardly toward the mouth 16 thereof. The rim 18 of the reservoir bordering the mouth 16 is substantially planar and horizontal so as to define a ledge upon which the hanger rods 20 of the hanger assembly that has been broadly designated by numeral 22 rest. The remaining elements of the hanger subassembly comprise multi-apertured hanger straps 24, the design, location and function of which will be described in detail presently.

Apart from the hanger assembly just mentioned, the remainder of the hot top 10 consists of several insulating elements, a fabric panel 26 and a post stiffener 28, all of which, when fastened together in the assembled relation shown in FIGS. 1 and 2, define an essentially uninterrupted wall shielding the interior surface of the mold reservoir against the loss of heat from the molten steel therethrough. Several of these elements are combined into two unitary foldable subassemblies that have been designated broadly by reference numeral 30 and which, apart from the hanger rods 22, cooperate with a pair of stiffener-reinforced posts 32 to'define essentially a four-piece hot top. The elements combined in each foldable subassembly 30 comprise the hanger straps 24, two generally trapezoidal wall sections 34 and 36, a corner wall section 38, a fabric panel and an outside cornerpiece 42. The latter subassembly 30 together with the method of forming same constitutes the principle novel feature of the present invention, the stiffener-reinforced posts 32 being basically the same as those used to hold the individual wall panels together in my earlier application already identified. These two reinforced posts 32, in other words, while remaining essential to the combination, function as keystones in exactly the same way to hold the subassemblies 30 in assembled relation as four like elements did in my previous eight-piece hot top. Accordingly, a detailed analysis will be made of subassemblies 30 at this time for which purpose reference will be made to FIGS. 1-6, inclusive.

Each subassembly 30 has a single panel of fabric 40, preferably of a type having a relatively loose or open weave like unbleached muslin, burlap, etc., atop which the three wall sections 34, 36 and 38 are formed. While each of these wall sections could be formed separately and then glued or otherwise attached to the fabric panel, the preferred method of making the subassemblies is to first dip the fabric panel in a liquid composition capable of imparting to it a measure of heat resistance. A suitable composition for this purpose is the one revealed in my earlier application, namely, one containing silica flour, starch and lignin sulfonate.

After the panel has been thus impregnated, it is laid on a platen and the straps 24 are placed in their proper locations atop thereof prior to bending their lower ends to form books 44 as shown by broken lines in FIG. 5. Next, the interior wall elements are formed by compacting a moist powdered refractory composition into thick trapezoidal blocks atop each fabric panel and strap laid thereon. The choice of ingredients and the proportions thereof found in the refractory composition used in my earlier eight-piece hot top are quite satisfactory for the present sub-assembly 30 as are the method of working it into the fabric panel and curing same preparatory to adding the exterior comer block 42. Of course, the main difference lies in forming not one, but three separate and distinct wall panels 34, 36 and 38 atop a single fabric panel 40 in edge-to-edge relation with V-shaped joints 46 therebetween that render them foldable using the fabric as the common hinge-forming element. The remaining differences comprise molding the straps as an integral part of the assembly, bending the lower projecting strap ends over to form hooks 44 in supporting relation to the lower margins of end wall sections 34 and 36 after the partially-completed subassembly has been cured and, finally, gluing or otherwise attaching corner block 42 to the exterior face of the fabric panel so as to cooperate therewith and with the middle wall section 38 to define an integral comer post basically similar in cross section to individual comer posts 32.

The particular shape and dimension of the three interior wall sections 34, 36 and 38 depend upon the shape and taper of the mold reservoir. Once folded into right-angle comer-forming relation, the top and bottom edges of each subassembly 30 will, of course, be essentially coplanar and horizontal when positioned inside the ingot mold reservoir. Similarly, the exact shape of the frusto-conical slice with the chordal cross sections represented by exterior corner block 42.can easily be determined with a few simple geometrical calculations once the shape of the reservoir comers and their taper is known.

FIGS. 7, 8 and 9 to which line of reference will now be made, show the individual corner posts 32 along with their stiffening members 28, that have been disclosed and claimed in my previous application already identified and which function in the same manner and for the same purpose, namely, as keystones to hold the two panel subassemblies 30 together in assembled relation when placed in the gaps left at one set of diagonal corners. The stiffeners prevent the corner posts from fracturing during shipment and handling as well as when driven into the comers with a mallet or similar hammering tool. Of course, while the reinforced corner post shown is preferred, unreinforced ones of the type found in the prior art could be substituted therefor.

Once again with reference to FIGS. 1 and 2, the hanger assembly 22 will be described in detail. The straps 24 each have the portions thereof projecting above the top margins of their respective panels provided with a series of 'several apertures 48 spaced one above the other. These apertures are arranged in horizontally aligned pairs in the two straps 24 of each panel subassembly 30 so that with the rods 20 passed therethrough as shown, such rods will rest atop the reservoir rim l8 and hold the hot top spaced a uniform distance beneath the latter while the individual corner posts are being inserted. This procedure eliminates the need for auxiliary jigs and, once the assembly is complete, tests have shown that the molten steel can be poured right over the rods 20 without disturbing the hot top or interferring with its insulating function. The multipleapertured straps allow the hot top to be raised or lowered within the ingot mold reservoir provided the taper of the latter is not so great that moving the subassemblies up or down will narrow or widen the gaps therebetween to an extent where the individual corner posts can no longer function as keys capable of locking them in assembled relation.

The hooks 44 on the lower ends of the straps cradle the lower margins of their respective wall-sections and, even if the bond between the straps and their wall sections were to break loose, these hooks would still function to support the subassemblies in proper position. Actually, one could eliminate the rods altogether and bend the apertured portions of the straps out and down until they hook over the rim of the mold reservoir, however, the hanger assembly using the rods is much preferred from several standpoints, not the least of which are the ease with which it allows the hot top to be installed and stripped from the ingot.

What is claimed is:

1. The insulating hot top which comprises:

a pair of foldable subassemblies and a pair of comer posts adapted to cooperate with one another in interlocked relation to define an uninterrupted layer of insulation sheathing the interior surfaces of an ingot mold reservoir, each of said foldable subassemblies including a single sheet of foldable fabric sized to cover the adjacent interiorwall surfaces and the corner therebetween of the reservoir, three individual panels of insulating material fastened to the inside surface of the fabric sheet in edge-to-edge relation so as to define two end panels and a center panel and a corner piece fastened to the exterior surface of the fabric sheet opposite the center panel, the adjacent edges of the three panels being beveled to mate with one another in comerforming relation when folded, the remote edges of the end panels of one subassembly cooperating with the opposite remote edges of the other subassembly to define a pair of upwardly divergent gaps in opposite corners of said reservoir, and the exterior surface of said corner piece being shaped to conform with the inside corner of the mold reservoir while the interior surface thereof is adapted to mate with the adjacent outside surface of said center panel and retain the fabric therebetween; and, each corner post of the pair thereof comprising a vertically elongate wedge-shaped block of insulation material shaped and adapted to be wedged into the gaps left between the foldable subassemblies so as to maintain same in assembled relation.-

2. The insulating hot top as set forth in claim 1 in which: each corner piece cooperates with one of the vidual cornerposts. 

1. The insulating hot top which comprises: a pair of foldable subassemblies and a pair of corner posts adapted to cooperate with one another in interlocked relation to define an uninterrupted layer of insulation sheathing the interior surfaces of an ingot mold reservoir, each of said foldable subassemblies including a single sheet of foldable fabric sized to cover the adjacent interior wall surfaces and the corner therebetween of the reservoir, three individual panels of insulating material fastened to the inside surface of the fabric sheet in edge-to-edge relation so as to define two end panels and a center panel and a corner piece fastened to the exterior surface of the fabric sheet opposite the center panel, the adjacent edges of the three panels being beveled to mate with one another in corner-forming relation when folded, the remote edges of the end panels of one subassembly cooperating with the opposite remote edges of the other subassembly to define a pair of upwardly divergent gaps in opposite corners of said reservoir, and the exterior surface of said corner piece being shaped to conform with the inside corner of the mold reservoir while the interior surface thereof is adapted to mate with the adjacent outside surface of said center panel and retain the fabric therebetween; and, each corner post of the pair thereof comprising a vertically elongate wedge-shaped block of insulation material shaped and adapted to be wedged into the gaps left between the foldable subassemblies so as to maintain same in assembled relation.
 2. The insulating hot top as set forth in claim 1 in which: each corner piece cooperates with one of the center insulating panels and the layer of fabric therebetween to define an integral corner post having a horizontal cross section similar in shape to that of the individual cornerposts. 